Length & Width

[VTFogg]

My UJ Pirogue is approximately 15' 11" long and the bottom of the widest rib measures 24.5" wide. Uncle John's plans show the wide rib place at the center of the boat when using 3 ribs. Is 24.5" too narrow for this length, thereby adversely affecting stability while increasing speed? I plan to take the boys out fishing on the creek and some of the area ponds, so good stability is important for this boat.

What if I were to move the wide rib back 12" and instead of making a 4th rib, I were to move the front rib back a bit, and build a reinforcing watertight bulkhead at the bow? Do I have to make another rib?

Thanks for your thought you most honorable boat builders! - VTFogg

Dang, it's 18 below out there and they say headed to -25 - Now that's fresh air!

 

[hairymick]

Hi Foggy,

I can think of no reason not to widen a UD pirogue if you are chasing stability.

I would proportionately widen all three ribs ie to 30ins centre and increase the end ones by a like percentage. I think a couple of blokes here have widened UJs.

If you want air-tight compartments for flotation, I can think of no reason why not to install bulkheads and decks at each end.

All moving the centre rib back will do is to give you an assymetrical hull shape ie bigger in the back than the front. I don't think it will increase stability. (might iomprove inline performance for a solo boat though).

 

[Bwing96]

I know many have crossed this bridge before and now that I have heard that notorious cracking sound, I will now ask for advice.

Overall length is 11' with 11" sides How wide should it be at the top of the sides if the width at the bottom is 25" ?

I do know 37" at the top and 24 at the bottom won't work which would have been a 25 degree angle.

What I have now is about 12 degrees on the sides.

 

[oldsparkey]

The standard Uncle Johns Pirogue is 31 inches at the top.

Some guys have built them at 15 1/2 feet ,or longer , and added a 2nd center rib , when they do that all 4 ribs are spaced evenly. It makes the center of the boat a little wider and offers a person the ability of standing while fishing.

I made one at 18 and bobbed off the stern section to make it 17 in case I wanted to put a trolling motor on it which I never did. It was made with only three ribs and was very solid in the water , a friend of mine has it for his use today.

That cracking sound could of been the side boards trying to separate from the ribs if you don't have a outside rub rail on the boat. Without it on there and you try to pick it up by yourself there is a good chance of breaking a rib on the boat. The sides will try to flex outward when the boat is picked up.

Chuck.

 

[Bwing96]

The cracking was the ply itself. It broke right in the center and broke the rib too. I know now I was trying to bring the ends together to attach to the stem with the center rib temporarily screwed to the floor.

I have decided to got with 24" @ the bottom and almost 30" @ the top.

 

[oldsparkey]

I have never done it that way , always bring the ends together and epoxy them in place , then go back and temporally put the ribs in to mark where they will be.

Then I install the ribs and when they have set up put on the outer railing for added support for when I am moving the boat around and then the floor.

Never had a problem but have heard a lot of horror stories from the guys who do it differently and even helped repair some of the damage if they live fairly close to me.

Chuck.

 

[Bwing96]

That makes sense, will make a note of that for boat #2

When you epoxy the sides to the stems do you go ahead and fiber glass it after it sets up ?

When you make the rub rail if your material isn't long enough do you use a lap joint on it ?

After the bottom is in place and fillet is done do you tape the outer seam and then completely cover the bottom and sides giving this area 2 layers ?

 

[oldsparkey]

I glass the boat after it is all together and everything is right.
On the rub rails I use a butt joint or one solid piece of molding , our local Home Depot has them in strips at 18 feet.
I do it one of two ways , the safe way is to tape the seams after filleting them and then glass over them or take a short cut and just fillet the seams and then glass over them.

Chuck